O’Mahony missed the defeat to Edinburgh last weekend but comes in at number 8 in place of James Coughlan.

It is one of a number of changes made by head coach Rob Penney.

The one change to the back-line sees Johne Murphy take the place of the injured Simon Zebo on the wing and in the pack Penney introduces O’Mahony as well as Damien Varley, BJ Botha, Donncha O'Callaghan.

Matt Healy returns on the wing, while Samoa international James So'oialo is named at full-back. The 24-year-old versatile back was brought on at inside centre last week at the Sportsground in what was his first Connacht appearance.

Up front, Galway-born Andrew Browne replaces the injured John Muldoon at blindside flanker.

Speaking ahead of the trip to Italy, Lam said: "Losing John Muldoon to injury, along with Eon McKeon and Willie Faloon, was a huge blow to our back row. But Andrew Browne comes in as a straight replacement at six and has plenty of experience in that position.

"Matt Healy comes back in after injury and we Iook forward to seeing him continue the form he showed in the opening weeks of the season.

"James So'oialo starts in his preferred international position of 15 which gives Gavin Duffy a well-deserved break and a chance to make an impact from the bench. And Craig Ronaldson gets a second start at inside centre after such an encouraging performance against Saracens.”

Man of the match from the Tigers game, Roger Wilson, moves from blindside flanker to Number 8 as Nick Williams misses the game with a calf injury. Robbie Diack is promoted from the bench to start at 6.

All Black prop John Afoa is named as a substitute and is in line to make his first appearance of the season for Ulster having recovered from the calf injury that has kept him out since the summer.